Based on the data seen in your graphs, according to me, this is a time series modelling problem and a model like ARIMA (Autoregressive Integrated Moving Model Average) would be a better fit.
Since you mentioned that you're starting (you've probably done a lot by now) here's a tutorial by Dr Jason Brownlee on implementing ARIMA on Python (In: ARIMA for time series forecasting with Python. This is for in sample prediction : if, where you want to predict valuevalues for which you already have to test the model) : ARIMA for time series forecasting with Python - In Sample Prediction .
Refer this one forFor out of sample Prediction see: Time Series ARIMA model for forecasting with Python - Out of sample prediction